An infant weighing 6 pounds 3 ounces has morphine 0.5 mg IV q 2 hours prn ordered for post op pain. The recommended dosage for a child is 0.1-0.2 mg/kg/dose q2-4 hours prn. Prove mathematically the ordered dose by the physician (mg/kg/dose) and is it safe to give.
The Correct Answer and Explanation is:
To assess if the morphine dose ordered for the infant is safe, we first need to convert the infant’s weight from pounds and ounces to kilograms and then calculate the recommended dosage based on the weight.
Step 1: Convert the infant’s weight to kilograms
- The infant weighs 6 pounds and 3 ounces.
- 1 pound = 16 ounces, so 3 ounces = 3/16 pounds.
- Total weight in pounds:
6+316=6.1875 pounds6 + \frac{3}{16} = 6.1875 \, \text{pounds}6+163=6.1875pounds - 1 pound = 0.453592 kg, so the weight in kilograms is:
6.1875×0.453592=2.806 kg6.1875 \times 0.453592 = 2.806 \, \text{kg}6.1875×0.453592=2.806kg
Step 2: Calculate the recommended morphine dose
The recommended dose of morphine is 0.1–0.2 mg/kg/dose every 2–4 hours as needed.
- Lower range dose:
0.1 mg/kg×2.806 kg=0.2806 mg0.1 \, \text{mg/kg} \times 2.806 \, \text{kg} = 0.2806 \, \text{mg}0.1mg/kg×2.806kg=0.2806mg - Upper range dose:
0.2 mg/kg×2.806 kg=0.5612 mg0.2 \, \text{mg/kg} \times 2.806 \, \text{kg} = 0.5612 \, \text{mg}0.2mg/kg×2.806kg=0.5612mg
Thus, the recommended dosage range for the infant is 0.2806 mg to 0.5612 mg per dose.
Step 3: Compare the ordered dose
The physician ordered 0.5 mg IV every 2 hours as needed.
Step 4: Determine if the dose is safe
- The physician’s ordered dose of 0.5 mg falls within the recommended dosage range (0.2806 mg to 0.5612 mg). Therefore, the dose of 0.5 mg per dose is safe based on the weight and the recommended dosage guidelines.
Explanation:
It is critical to assess medication dosages for infants based on weight due to their smaller body size and differences in drug metabolism compared to adults. Morphine is an opioid used to manage moderate to severe pain, and it must be dosed carefully in infants to avoid side effects such as respiratory depression. The recommended range of 0.1-0.2 mg/kg/dose for infants ensures that the dosage is effective without exceeding toxic levels. The physician’s order of 0.5 mg is within the safe range for this infant weighing 2.806 kg. As long as the infant is monitored for adverse effects, including sedation and respiratory depression, the ordered dose can be considered safe and appropriate.